James and G600. Since you are going the same way as me, using Toroidal transformer&Lundahl’s. I was told a trick by Hans from Amplimo.nl. It’s easy to reduce the voltage of a toroidal transformer, by unwinding the plastic wrapper and then unwinding the secondary winding. One winding will equate roughly to one volt. Once the desired voltage reached, resolder leads and re-wrap the foil. In this way toroidal transformer are very flexible. Just thought you’d be interested.
Hello, Did find some nice information on transformers.....
the top is commonly called a "R-core", semi-toroidal - the windings are in balanced sections on the two bobbins - the core has a round cross section is actually 2 "C" cut cores clamped together
the bottom is a fully toroidal transformer with the windings in layers evenly spread over the toroidal core - it has less external magnetic field leakage but much higher pri-sec parasitic C
the fully toroidal construction used to be more expensive but with automated winding machines its higher material efficiency makes them cheaper, widely available
a undeserved reputation for "quality" is a holdover from the early days of expensive fully toroidal transformers
the low radiated magnetic field is a real advantage if you want a compact build with sensitive circuits crowded up against the transformer
but the high pri-sec C couples more line noise, the core saturates hard and in driving material cost down most are working near the edge of saturation in normal operation
EI laminated core, split bobbin transformers have the least pri-sec C, better saturation characteristics - but do have larger external magnetic field leakage - need more room, or shielding - but isolate better from line noise
the R core is somewhat in between, its dual split bobbins double the pri-sec C but partially cancel the magnetic field leakage
A few days ago someone did post some photos with a power supply using the so called split bobbins technique. I think one should also think about the garbage a lot of digital gear is giving back to the power lines.
Carefully location the transformer is always a good thing. If the power rating is big enough you can also pot it to reduce the influence of the magnetic field.
The R core has 2 secondary windings can put them in parallel to double the A rating or put them in series, use 2 diodes and have the centre tap like the negative side of the power supply. I dont know which one will be better. Of course one needs to know before ordering.
Sincere greetings, Edward
the top is commonly called a "R-core", semi-toroidal - the windings are in balanced sections on the two bobbins - the core has a round cross section is actually 2 "C" cut cores clamped together
the bottom is a fully toroidal transformer with the windings in layers evenly spread over the toroidal core - it has less external magnetic field leakage but much higher pri-sec parasitic C
the fully toroidal construction used to be more expensive but with automated winding machines its higher material efficiency makes them cheaper, widely available
a undeserved reputation for "quality" is a holdover from the early days of expensive fully toroidal transformers
the low radiated magnetic field is a real advantage if you want a compact build with sensitive circuits crowded up against the transformer
but the high pri-sec C couples more line noise, the core saturates hard and in driving material cost down most are working near the edge of saturation in normal operation
EI laminated core, split bobbin transformers have the least pri-sec C, better saturation characteristics - but do have larger external magnetic field leakage - need more room, or shielding - but isolate better from line noise
the R core is somewhat in between, its dual split bobbins double the pri-sec C but partially cancel the magnetic field leakage
A few days ago someone did post some photos with a power supply using the so called split bobbins technique. I think one should also think about the garbage a lot of digital gear is giving back to the power lines.
Carefully location the transformer is always a good thing. If the power rating is big enough you can also pot it to reduce the influence of the magnetic field.
The R core has 2 secondary windings can put them in parallel to double the A rating or put them in series, use 2 diodes and have the centre tap like the negative side of the power supply. I dont know which one will be better. Of course one needs to know before ordering.
Sincere greetings, Edward
One winding will equate roughly to one volt.
Are you sure about that?
Does a 12 Volt(sec) transformer only have 12 secondary windings?
Are you sure about that?
Does a 12 Volt(sec) transformer only have 12 secondary windings?
Soory could not edit my previous post
Here is another good link (SoundStage! Max dB - The High-End Mythology of the Toroidal Power Transformer (07/1998)) on this topic at Sound Stage...
I have reporduced some of it here for prosterity...
The High-End Mythology of the Toroidal Power Transformer
Some background about how AC power is delivered to residences
When AC power is transmitted across long distances, high voltages increase transmission efficiency and decrease the size and weight of cables needed to carry the power. However, high voltages in the home are quite dangerous so power companies build sub-stations to reduce the voltage levels for residential and light business use. In the US these substations produce three-phase electrical power. Two of the three phases are what is typically delivered to residences. These electrical phases each carry (nominally) 120v rms AC referenced to the neutral wire… all three phases use the same neutral wire/connection/reference. When two phases are supplied to a home or business, you have three wires coming into the house. One of them is neutral. You can connect the two 120v lines to a single electrical outlet and get 208/240 AC volts which is used to power electric dryers, electric ranges and stoves, electric water heaters and other heavy duty electrical appliances.
The thing to remember about this three-phase and two-phase power delivery system is that the loads on each phase must remain balanced or you can get a DC offset to the AC voltage. If power becomes unbalanced in any one phase, a DC offset appears in your AC power. These DC offsets can be transient or long-term. You still get the 120 (nominal) rms volts, but instead of it being a sine wave with positive peaks of about 170 volts and negative peaks of -170 volts, the sine wave is shifted up or down. A +5-volt DC offset would result in positive peaks of 175 volts and negative peaks of –165 volts (approximate voltages). A –6-volt DC offset would result in peaks of +164 and –176. All because the power becomes unbalanced, i.e. there is more load on one or two phases than on the remaining phase. These DC offsets can very dynamic, changing constantly as residences and businesses consume power and turn machinery on and off. Some of the offsets cancel each other out, resulting in no DC offset, but it is not terribly unusual to have transient DC offsets in power delivered to homes in the US. In Europe, depending on the country, some power grids are owned by the country and are actually running at full capacity or even higher than full capacity. In those situations, the potential for DC offset to exist in the power delivered to residences is quite high.
Two transformer types versus DC offset
What does DC Offset have to do with the AC Power Transformer? Everything! You see, the toroid transformer is very intolerant of DC offset being present at the input (primary winding). In fact, if there is any DC at all in the AC power supplied to the typical AC Power toroid transformer, the laminated metal core of the transformer "saturates" and the transformer no longer operates as designed. The result is often high levels of audible noise from the transformer as well as very high levels of noise getting into the power supply of the component.
When an EI-frame transformer is used, the DC offset problem disappears. The EI-frame transformer continues to supply AC power of the proper voltage with all the noise elimination capabilities designed into the EI-frame transformer still operating perfectly. Industry outside of high-end audio has not widely adopted the AC toroid power transformer because of these very problems. The majority of transformers in general use outside of high-end audio equipment are actually EI-frame transformers.
The main advantages of EI-frame transformers over toroidal transformers are: less susceptibility to core saturation from DC offset; air gaps which act as pressure relief valves for high density magnetic flux in the core. Saturation of the transformer core results in an energy build-up in the core of the transformer. Toroid transformers are wound with the core completely covered by the primary and secondary wires. The toroid core is completely isolated from ground. In the EI-frame transformer, however, a significant portion of the core is external and is attached directly to the chassis of the equipment it is installed in. This gives any energy build-up in the core a direct path to the chassis ground of the component. The other advantage EI-frame transformers have is the small air gaps that are present because of the gaps present when the two parts of the frame/core are put together. These air gaps act as pressure relief valves for the magnetic flux in the core further enhancing the transformer’s resistance to core saturation. You can have an air gap in the core of a toroidal power transformer, but this requires machining a gap perhaps 0.020" wide, about the thickness of a sheet of paper. This is not a trivial task and adds significantly to manufacturing cost of the toroid transformer. It is very rare to encounter toroid transformers with air gaps because of the cost and difficulty of machining such a thin slit across the laminations that make the metal donut. These are two of the reasons EI-frame transformers, when properly designed, can provide better audible performance in your audio components.
What’s the catch?
It seems like an EI-frame transformer ought to be a 100% shoe-in for high-end audio components, but there is a "dark side" to the EI-frame transformer. They radiate a rather significant magnetic field from the exposed windings (which are sometimes covered by rounded metal end bells). Low level audio signals such as those found in preamplifiers and gain stages prior to the output stage of amplifiers are small enough in magnitude, that passing them through a strong magnetic field would induce hum in the audio signal. In a preamplifier, this is easy to avoid. Put the power supply in an external enclosure as many preamp manufacturers do, especially those who use EI-frame power transformers. In an amplifier, the answer is to "aim" the transformer correctly. There is a big "shadow" in the magnetic field where the laminated plates are...the magnetic field is strong only outside the end-bells of the transformer. Aim the EI-frame transformer so that the core points towards the audio signal processing and so that the "bells" point to the sides and the radiated magnetic field won’t bother the audio circuits inside the amp. But putting an EI-frame in a tightly packed multi-channel amp or receiver is just about impossible...there just isn’t enough room to stay away from the radiated magnetic field. In those applications, you will almost always find toroidal power transformers. You can jam a toroid right into the middle of five amplification channels and have no problems from magnetic fields. Magnetic shielding for an EI-frame transformer is also possible, but it tends to be expensive and heavy.
Why lavish so much attention on the transformer?
When you look realistically at what happens in an audio component...you know the answer. The signal leaving the component existed only as AC power from your wall outlet only milliseconds before it is on the way to the next component or to the loudspeakers. AC power is the raw material for the output of the component. Make beer, wine, scotch or bourbon with bad water and you get a bad product. Make an audio component with a generic off-the-shelf toroidal transformer and you are going to get a generic sounding component. It won’t be terrible, but it will fail to scale the heights of what is possible.
So an EI-frame transformer is always better than a toroidal transformer?
Hmmm. Good question. I am tempted to say "yes" because really excellent toroidal transformers are apparently difficult, if not impossible to purchase off-the-shelf. However, finding great EI-transformers is no walk in the park either. But in general, being able to connect the core of the EI-frame transformer electrically to the chassis of the component and the air gaps created by the two-piece laminated core give even off-the-shelf EI-frame transformers some performance capabilities beyond what you can get from off-the-shelf toroidal transformers. If you know your magnetic theory (or your transformer vendor does), there are additional winding tricks that give EI-frame transformers 20dB to 30dB more noise rejection than typical toroidal transformers. This is very significant. 20dB less noise is 1/100th of the noise of the "reference" level. 30dB less noise is 1/1000th of the "reference" noise level. You might be able to find a toroid manufacturer who could do the custom winding, add an air gap and attach a ground wire to the core. You would pay two to three times the cost of an off-the-shelf toroid to get that level of performance. But you sure won’t find a toroid off the shelf that performs as well.
I’ve been lucky enough to speak to a variety of high-end manufacturers about AC power, transformers, and component design. Conversations with Richard Vandersteen, Mike VansEvers and Emil Rotar (Warner Imaging) have been most illuminating. Years ago, I never really gave power transformers much thought. The assumption was that because so many high-end manufacturers were using toroidal power transformers, toroids must be demonstrably superior. Imagine my surprise when I started noticing that many of the best sounding components I’ve experienced in my system have all had EI-frame transformers. Coincidence? I might have thought so before finding out so more about power and transformers. Now I’m convinced that cleverly done EI-frame transformers could/should give us better sounding high-end audio components.
Here is another good link (SoundStage! Max dB - The High-End Mythology of the Toroidal Power Transformer (07/1998)) on this topic at Sound Stage...
I have reporduced some of it here for prosterity...
The High-End Mythology of the Toroidal Power Transformer
Some background about how AC power is delivered to residences
When AC power is transmitted across long distances, high voltages increase transmission efficiency and decrease the size and weight of cables needed to carry the power. However, high voltages in the home are quite dangerous so power companies build sub-stations to reduce the voltage levels for residential and light business use. In the US these substations produce three-phase electrical power. Two of the three phases are what is typically delivered to residences. These electrical phases each carry (nominally) 120v rms AC referenced to the neutral wire… all three phases use the same neutral wire/connection/reference. When two phases are supplied to a home or business, you have three wires coming into the house. One of them is neutral. You can connect the two 120v lines to a single electrical outlet and get 208/240 AC volts which is used to power electric dryers, electric ranges and stoves, electric water heaters and other heavy duty electrical appliances.
The thing to remember about this three-phase and two-phase power delivery system is that the loads on each phase must remain balanced or you can get a DC offset to the AC voltage. If power becomes unbalanced in any one phase, a DC offset appears in your AC power. These DC offsets can be transient or long-term. You still get the 120 (nominal) rms volts, but instead of it being a sine wave with positive peaks of about 170 volts and negative peaks of -170 volts, the sine wave is shifted up or down. A +5-volt DC offset would result in positive peaks of 175 volts and negative peaks of –165 volts (approximate voltages). A –6-volt DC offset would result in peaks of +164 and –176. All because the power becomes unbalanced, i.e. there is more load on one or two phases than on the remaining phase. These DC offsets can very dynamic, changing constantly as residences and businesses consume power and turn machinery on and off. Some of the offsets cancel each other out, resulting in no DC offset, but it is not terribly unusual to have transient DC offsets in power delivered to homes in the US. In Europe, depending on the country, some power grids are owned by the country and are actually running at full capacity or even higher than full capacity. In those situations, the potential for DC offset to exist in the power delivered to residences is quite high.
Two transformer types versus DC offset
What does DC Offset have to do with the AC Power Transformer? Everything! You see, the toroid transformer is very intolerant of DC offset being present at the input (primary winding). In fact, if there is any DC at all in the AC power supplied to the typical AC Power toroid transformer, the laminated metal core of the transformer "saturates" and the transformer no longer operates as designed. The result is often high levels of audible noise from the transformer as well as very high levels of noise getting into the power supply of the component.
When an EI-frame transformer is used, the DC offset problem disappears. The EI-frame transformer continues to supply AC power of the proper voltage with all the noise elimination capabilities designed into the EI-frame transformer still operating perfectly. Industry outside of high-end audio has not widely adopted the AC toroid power transformer because of these very problems. The majority of transformers in general use outside of high-end audio equipment are actually EI-frame transformers.
The main advantages of EI-frame transformers over toroidal transformers are: less susceptibility to core saturation from DC offset; air gaps which act as pressure relief valves for high density magnetic flux in the core. Saturation of the transformer core results in an energy build-up in the core of the transformer. Toroid transformers are wound with the core completely covered by the primary and secondary wires. The toroid core is completely isolated from ground. In the EI-frame transformer, however, a significant portion of the core is external and is attached directly to the chassis of the equipment it is installed in. This gives any energy build-up in the core a direct path to the chassis ground of the component. The other advantage EI-frame transformers have is the small air gaps that are present because of the gaps present when the two parts of the frame/core are put together. These air gaps act as pressure relief valves for the magnetic flux in the core further enhancing the transformer’s resistance to core saturation. You can have an air gap in the core of a toroidal power transformer, but this requires machining a gap perhaps 0.020" wide, about the thickness of a sheet of paper. This is not a trivial task and adds significantly to manufacturing cost of the toroid transformer. It is very rare to encounter toroid transformers with air gaps because of the cost and difficulty of machining such a thin slit across the laminations that make the metal donut. These are two of the reasons EI-frame transformers, when properly designed, can provide better audible performance in your audio components.
What’s the catch?
It seems like an EI-frame transformer ought to be a 100% shoe-in for high-end audio components, but there is a "dark side" to the EI-frame transformer. They radiate a rather significant magnetic field from the exposed windings (which are sometimes covered by rounded metal end bells). Low level audio signals such as those found in preamplifiers and gain stages prior to the output stage of amplifiers are small enough in magnitude, that passing them through a strong magnetic field would induce hum in the audio signal. In a preamplifier, this is easy to avoid. Put the power supply in an external enclosure as many preamp manufacturers do, especially those who use EI-frame power transformers. In an amplifier, the answer is to "aim" the transformer correctly. There is a big "shadow" in the magnetic field where the laminated plates are...the magnetic field is strong only outside the end-bells of the transformer. Aim the EI-frame transformer so that the core points towards the audio signal processing and so that the "bells" point to the sides and the radiated magnetic field won’t bother the audio circuits inside the amp. But putting an EI-frame in a tightly packed multi-channel amp or receiver is just about impossible...there just isn’t enough room to stay away from the radiated magnetic field. In those applications, you will almost always find toroidal power transformers. You can jam a toroid right into the middle of five amplification channels and have no problems from magnetic fields. Magnetic shielding for an EI-frame transformer is also possible, but it tends to be expensive and heavy.
Why lavish so much attention on the transformer?
When you look realistically at what happens in an audio component...you know the answer. The signal leaving the component existed only as AC power from your wall outlet only milliseconds before it is on the way to the next component or to the loudspeakers. AC power is the raw material for the output of the component. Make beer, wine, scotch or bourbon with bad water and you get a bad product. Make an audio component with a generic off-the-shelf toroidal transformer and you are going to get a generic sounding component. It won’t be terrible, but it will fail to scale the heights of what is possible.
So an EI-frame transformer is always better than a toroidal transformer?
Hmmm. Good question. I am tempted to say "yes" because really excellent toroidal transformers are apparently difficult, if not impossible to purchase off-the-shelf. However, finding great EI-transformers is no walk in the park either. But in general, being able to connect the core of the EI-frame transformer electrically to the chassis of the component and the air gaps created by the two-piece laminated core give even off-the-shelf EI-frame transformers some performance capabilities beyond what you can get from off-the-shelf toroidal transformers. If you know your magnetic theory (or your transformer vendor does), there are additional winding tricks that give EI-frame transformers 20dB to 30dB more noise rejection than typical toroidal transformers. This is very significant. 20dB less noise is 1/100th of the noise of the "reference" level. 30dB less noise is 1/1000th of the "reference" noise level. You might be able to find a toroid manufacturer who could do the custom winding, add an air gap and attach a ground wire to the core. You would pay two to three times the cost of an off-the-shelf toroid to get that level of performance. But you sure won’t find a toroid off the shelf that performs as well.
I’ve been lucky enough to speak to a variety of high-end manufacturers about AC power, transformers, and component design. Conversations with Richard Vandersteen, Mike VansEvers and Emil Rotar (Warner Imaging) have been most illuminating. Years ago, I never really gave power transformers much thought. The assumption was that because so many high-end manufacturers were using toroidal power transformers, toroids must be demonstrably superior. Imagine my surprise when I started noticing that many of the best sounding components I’ve experienced in my system have all had EI-frame transformers. Coincidence? I might have thought so before finding out so more about power and transformers. Now I’m convinced that cleverly done EI-frame transformers could/should give us better sounding high-end audio components.
That's what Hans told me, but coming to think of it, you are probably right, less then one volt per winding. Which makes dialing in the correct voltage even easier. 🙂
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Hi Edward,
On the dac board I use 2x 100uf/25v silmic, than downstream 47uf/25v silmic. For the Vcom pins I use 2x47uf/16v silmic. For digital oscon 47uf/20v. This is for one channel.
For the raw power supply I use 2200uf/25v silmic (type1) and after the dropping resistor (for digital) I use 2x 560uf/20v
I will also try shunt input (and common mode) now the dac boards are run in. ( if I can find the time between painting the woodwork of my house 😉)
Thanks for all your input!
Regards,
Hi All, I have been listening to the DAC for almost a year now and finally got around to switching the caps out for transformers. I am utterly shocked at how much the cap was influencing and adding to the sound. Dropping the caps has proven to be a monumental tweak in my system. Highly recommended!!!
Good to hear, I'm building a choke based PS at the moment. Can you share some details on what you build/changed? In what way did the DAC improve?
Hi Chanh,
As our friend palmito says you can start ordering the S03 pcb to acko and get from him the schematic and the relevant bom. As requested from acko I can't public here the schematic but if you have already the bom in the hands here is the list of what you NO NEED to populate in the board to make the isolator/reclock working with the DDDAC:
R3, R4, R5, R7, R13, R18, C7, C13, C16, C17, FB1, FB4, Q2, U5, U8.
You need only one XO and you can install it in the X1 or X2 position as you like.
Another choice that you have to do is regarding the various voltage inputs.
As you can see in the schematic you have many choice depending on what you have available.
This is my configuration but is not a "must":
J2 - External 3,3V. In this case I don't populate all the components relevant to the J1.
J3 - External 5V for the 3,3VD
J4 - External 3,3V for the 2 flip flop. I use J4 because I have 3,3V available from the dac motherboard but if you have the 5V available you can populate the relevant regulator using the J6 instead of J4
The connections are quite simple following the schematic and this is the pin to pin connection (I attach for reference the S03 input connector):
RPI -- to -- S03
pin 2 ----- pin 2 3,3V
pin 3 ----- pin 7 BCK
pin 4 ----- pin 6 LR
pin 6 ----- pin 8 DAT
pin 8 ----- anyone of the pin GND
The only output connections that you need for the DDDAC are BCK, LR and DATA. Those in the S03 are only u.fl and here I realize a small pcb/connector to use the u.fl cables. If you don't want to use the u.fl connectors I think that you can sold a small cable directly to the u.fl pads BUT I am not 100% sure, maybe somebody can advise you better than me about.
If you don't use the +/- from the DDDAC at the J4/J6 you need to connect a GND from the DDDAC to the S03.
I hope that you can succeed with the S03... is really a BIG step ahead.
Best Regards,
Enrico
PS: Thanks to All of you in this amazing thread... to Doede first of all to share with us this FANTASTIC DDDAC and to palmito and supersurfer that time to time take me by hands up to this point... my next step will be the Tent shunts if one day they will reach korea 🙂
Attachments
I have been wondering about this for the 4 x caps just before the regulators on each DAC board, because as far as the circuit after it is concerned, the shunt regulator behaves like a very low ESR, very fast reacting capacitor. But unlike a decoupling capacitor, it kind of isolates the v+ after it from the v+ before it.
Guido's guidelines for placement and integration state that the shunt regulator should be placed as close as possible to the load and that just before it you should ideally put something like a 10uf decoupling capacitor. When I asked, he stated OSCON type caps would be great for this regardless of what the shunt is driving.
So, I understand that typically OSCON type caps are better for digital circuits and something like a Silmic or Panasonic FC are better for analog circuits, but we're not talking about caps directly for those circuits are we? We're talking about caps for the regulators. So according to Guido's recommendations, we should be ideally using OSCON caps just before any shunt regulator.
Or is it not that simple?
Also, I've got some leads made up for my scope now, so I hope to do some power supply testing and measurements soon, including testing different caps on the dac and mainboards 🙂 Any recommendations for what I should be looking for there? Is there a specific type of tone or sound which I can play as a test tone during these measurements which will test things the most?
In regard to caps, nothing is easy unfortunately.... my experience ist that it can be pretty personal what caps you like..... also depending on how it fits into the sound of the rest of your chain. I would not say my choice for the Nichicons was totally arbitrary, but also I wanted to have a good cap at an affordable price and also with good availability. That is why I picked them. I still believe they are pretty good. The best in existence? Probably not. at least a point of discussion and experience I guess.... And from that point the tweaking can start if you like. just stating this cap or that cap is the best works for own results but might be a mal advise for some one else.... but keep sharing experience, it always helps finding starting points for further experiments 🙂
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...please pardon, although at least partly off topic, this should/would/could be the icing on the cake with all our DDDACs, and so I felt it justified to put it here:
...entering DSD128...
the one that I come across is an anthology of Eric Bibb, derived from master tape and recorded directly as DSD128
you might find it here:
dsdfile.com | A Selection of analogue Eric Bibb
there are only few albums at the moment, and only some are DSD128...
...for Bibb the following is available:
DSD64 (2.8MHz) Size: 1,9gb
DSD128 (5.6MHz) Size: 3,9gb
...as one can see easily, the amount of digital data between DSD64 and DSD128 is more as double as much... (so I ask myself, what are we listening to, when listening to a (perfectly) ripped CD (wav of flac) ? It is just a very small fraction of the original, it is just a tenth of the amount of data as with DSD128 !!! and then all the discussion about this mostly castrated source...
I have not yet listened to it, the file-ending is dsf, and at the moment I am not quite sure if it will play at all in foobar, because I cannot find a specific corresponding component being able to play it...
...or should the "normal" DSDIFF-decoder be sufficient ?
...entering DSD128...
the one that I come across is an anthology of Eric Bibb, derived from master tape and recorded directly as DSD128
An externally hosted image should be here but it was not working when we last tested it.
you might find it here:
dsdfile.com | A Selection of analogue Eric Bibb
there are only few albums at the moment, and only some are DSD128...
...for Bibb the following is available:
DSD64 (2.8MHz) Size: 1,9gb
DSD128 (5.6MHz) Size: 3,9gb
...as one can see easily, the amount of digital data between DSD64 and DSD128 is more as double as much... (so I ask myself, what are we listening to, when listening to a (perfectly) ripped CD (wav of flac) ? It is just a very small fraction of the original, it is just a tenth of the amount of data as with DSD128 !!! and then all the discussion about this mostly castrated source...
I have not yet listened to it, the file-ending is dsf, and at the moment I am not quite sure if it will play at all in foobar, because I cannot find a specific corresponding component being able to play it...
...or should the "normal" DSDIFF-decoder be sufficient ?
Hi Enrico,
Many thanks for your post! 🙂
Currently experience Pi i2s direct while waiting for the parts. For some reasons, I did occasionally hear cracks and pops on hires via Volumio. Has anyone experienced this abnormality too?
I now have received my Chokes and Cree Schotty diodes. Hopefully am able to construct similar raw ps like you Gents. No Shunts just yet, still waiting for Doede's responses w.r.t his findings and should a revise PCB are coming in near future?
Many thanks again!
Chanh
Many thanks for your post! 🙂
Currently experience Pi i2s direct while waiting for the parts. For some reasons, I did occasionally hear cracks and pops on hires via Volumio. Has anyone experienced this abnormality too?
I now have received my Chokes and Cree Schotty diodes. Hopefully am able to construct similar raw ps like you Gents. No Shunts just yet, still waiting for Doede's responses w.r.t his findings and should a revise PCB are coming in near future?
Many thanks again!
Chanh
Hello,
Thank you supersurfer for the reply.
I still have to decide what to do . Buy the dac this year and go for one board with shunts or wait if there will be a new board available and go for four boards in a nice set up.
With the power i allready have some idea which way to go. Probably R core transformer( i did see Jean Hiraga did use a 300Va model but i forget how many boards he is using) The one sold by selectronic in France also has a static shield and they arent that expensive. Have some chokes in stock but not the Lundahls. I have 400mH but they are 4.2 ohm so if i use them and late switch to lundahl which are 1.8 ohm i will need another transformer. Maybe i could use an universal transformer to find the best combination of chokes and then get a proper transformer.
Before that moment arrives there will be som,e opinions expressed on chokes for sure.
Sincere greetings, Edward
Thank you supersurfer for the reply.
I still have to decide what to do . Buy the dac this year and go for one board with shunts or wait if there will be a new board available and go for four boards in a nice set up.
With the power i allready have some idea which way to go. Probably R core transformer( i did see Jean Hiraga did use a 300Va model but i forget how many boards he is using) The one sold by selectronic in France also has a static shield and they arent that expensive. Have some chokes in stock but not the Lundahls. I have 400mH but they are 4.2 ohm so if i use them and late switch to lundahl which are 1.8 ohm i will need another transformer. Maybe i could use an universal transformer to find the best combination of chokes and then get a proper transformer.
Before that moment arrives there will be som,e opinions expressed on chokes for sure.
Sincere greetings, Edward
I had similair issue with Volumio (on the BBB though), I was able to solve some of the glitches by increasing the "buffer before ply" to 30%, in the General music daemon options. See if that works for you.
Gents, I've just wired the 9V secondaries to my capacitor input with chokes, I now have 13.5V at the 75 Ohm bleeder.
Maybe tomorrow I'll wire this to the DDDAC and see how Stefan's way to use Chokes sounds.
Edward, you are very strong to resist to the DDDAC !!
The article you pointed about power transformer is very good. I haven't see myself such premium quality EI-cores, with the winding tricks. I must contact again my trafo maker, and see what I can learn from him.
He offer me a C-core of improved quality, he confirmed what I read there http://www.vt4c.com/teach_room/choose_transformer.html :
"C-core: Very rare but it is a great core. There are double C core and normal C-core. Normal C-core just looks like an R-core cut into 2 pieces. The cut edge is an air gaps to prevent core saturation. It also allows the winding done externally. So, it has both advantages of EI and R-core. It has a slight low efficiency than R-core but much better than EI. It common used for many tens years in high-end equipment¡¦s and Audio PT, Choke, OPT and choke. Making a C-core is harder than a EI. So, cannot be cheap!"
Maybe tomorrow I'll wire this to the DDDAC and see how Stefan's way to use Chokes sounds.
Edward, you are very strong to resist to the DDDAC !!
The article you pointed about power transformer is very good. I haven't see myself such premium quality EI-cores, with the winding tricks. I must contact again my trafo maker, and see what I can learn from him.
He offer me a C-core of improved quality, he confirmed what I read there http://www.vt4c.com/teach_room/choose_transformer.html :
"C-core: Very rare but it is a great core. There are double C core and normal C-core. Normal C-core just looks like an R-core cut into 2 pieces. The cut edge is an air gaps to prevent core saturation. It also allows the winding done externally. So, it has both advantages of EI and R-core. It has a slight low efficiency than R-core but much better than EI. It common used for many tens years in high-end equipment¡¦s and Audio PT, Choke, OPT and choke. Making a C-core is harder than a EI. So, cannot be cheap!"
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New to this thread, a couple of questions.
Hi everyone,
I was very keen to try a NOS dac and, having read through this enthusiastic thread, have been ordered the 'complete DDAC set' with a single dac board. I will use this initially with an existing linear power supply.
I have a couple of questions:
1) Supersurfer, in post 1468 about the comparison of different DDAC's, wrote: 'The surprise of the day was number 4, this was a nice 2nd place'. This was James's single board DDDAC1794, with direct balanced output. This would appear to be a very economical option. What modifications, other than the direct o/p and modified power supply, had been applied to James's DDDAC1794? Tent shunts in the dac board....?
2) My amplifier is single ended and I want to upgrade the I/V resistors. Can I get away with fitting upgraded load resistors just in the +ve leg to the amp, leaving the standard resistors in the -ve leg? That way, I can justify the cost of the AN tantalums...
Thanks to all,
John T
Hi everyone,
I was very keen to try a NOS dac and, having read through this enthusiastic thread, have been ordered the 'complete DDAC set' with a single dac board. I will use this initially with an existing linear power supply.
I have a couple of questions:
1) Supersurfer, in post 1468 about the comparison of different DDAC's, wrote: 'The surprise of the day was number 4, this was a nice 2nd place'. This was James's single board DDDAC1794, with direct balanced output. This would appear to be a very economical option. What modifications, other than the direct o/p and modified power supply, had been applied to James's DDDAC1794? Tent shunts in the dac board....?
2) My amplifier is single ended and I want to upgrade the I/V resistors. Can I get away with fitting upgraded load resistors just in the +ve leg to the amp, leaving the standard resistors in the -ve leg? That way, I can justify the cost of the AN tantalums...
Thanks to all,
John T
Sounds like a good idea to me. I would imagine with the extra load from your dac, it will be close to 12v now